反应详情

39 g (154.6 mmol) of the title compound of Example 5a and 44.43 g (77.3 mmol) of 1,4,7-tris-(benzyloxycarbonyl)-1,4,7,10-tetraazacyclododecane (produced according to Chem. Soc., Perkin Trans. 1, 12:3329, 1991) and 85.14 g (616 mmol) of potassium carbonate in 800 ml acetonitrile are refluxed for 24 hours. Solid is filtered out, and the filtrate is evaporated to dryness in a vacuum. The residue is taken up in 700 ml of methylene chloride and extracted twice with 300 ml of water. The organic phase is dried on magnesium sulfate and concentrated by evaporation in a vacuum. The residue is chromatographed on silica gel (mobile solvent =methylene chloride/methanol 20:1).